How do I make a glass with a thicker bottom than top?
You can for instance use a solidify modifier set to vertex group, then paint the weights in weight paint mode.
First add a vertex group and in edit mode make sure to remove every weight from your vertices.

Then add a solidify modifier to your mesh, set the factor to something &gt; 0 so there is at least a bit of displacement with a weight 0.

Then go into vertex weight paint, with the ALT key pressed left-click on the bottom of your object, then drag your cursor up to the top and release the mouse button. You will see a gradient on your mesh :

Play with the solidify and the vertex group factor. Tweak a bit the mesh and use a negative thickness to get something approaching your image. Final result :